I didn't realise for a long time, but I looks back and see that somehow, upper caste kids always stuck together. There parents always had social events together, and even though we shared same society, other families weren't invited. Every 'class' has to have their own very public, very loud 'holidays'. Caste based marriages are pretty obvious, though that is changing slowly. People have biases in simple places, like simply knowing someone's surname means you can put them in a caste/category and then first impression is already made.
Things are changing, definitely, but slowly and not always in right direction. The 'reservation' or quotas in college admissions, government jobs and so on, created to make a level playing field is creating a new privileged class that is 'lower caste' in name only. This is creating new divide and I'm not sure thatcan be changed because suggesting otherwise is political suicide.